SHAFAQNA – Imam Sadeq (AS) was asked: What will make a believer resolute in his/her belief? Imam (AS) replied: Piety and staying away from sin. Imam Sadeq (AS) was asked again: What will cause the decline of the belief? Imam (AS) replied: Greed . Therefore, the decline of belief depends on greed and the one who is greedy must be ready to lose his/her belief .
 Osul, Page 259.
 Majalis, Page 174.